Electrochemical evaluation of the antioxidant activity of the extracts of persimmon and hawthorn from north of Iran

Free radicals, single-electron compounds that exist naturally in living systems and can change the structure of protein, fat, carbohydrates and DNA. Also, they cause the spontaneous oxidation of foods and consequently the harsh and bad taste of foods [1,2]. Clinical studies have shown that a diet rich in fruits and vegetables reduce the risk of cardiovascular diseases, cancer and other related disorders. These results are related to the presence of antioxidants compounds in the fruits and vegetables. Antioxidants are compounds that can deactivate free radicals [3].Electrochemical techniques are suitable tools for the determination of antioxidant capacity of compounds in the biological samples due to high selectivity and sensitivity [4]. In the present work, we investigated electrochemical evaluation of antioxidant capacity of persimmon and hawthorn fruits from north of Iran. Hence, definite amounts of dried persimmon and hawthorn samples were weighed and then extracted with different solvents such as Ethanol, Methanol and Hexane by soxhlet. After extraction, 250 µL of obtained extracts was diluted with 15 ml of phosphate buffer 0.1M (pH 5.5). Electrochemical responses were obtained with a three electrode system consisting of a glassy carbon electrode, a Pt wire and the Ag/AgCl/KCl 3M representing the working electrode, the counter electrode and the reference electrode, respectively. The antioxidant and redox profile of fruits extracts were characterized by means of cyclic voltammetry (CV), square wave pulse voltammetry (SWPV) and differential pulse voltammetry (DPV). The antioxidant potential expressed by electrochemical index (EI) was compared to the results obtained with the DPPH method.